How do I change the extension name on a NEC Elite DTU-16D phone? Feature key..then what???

SOURCE: flashing light

It sounds as if that particular extension is in Do Not Disturb.
From that phone, try Feature - 69 - Feature.

SOURCE: dtu 16d

did you get the email?

SOURCE: nec eletra elite dtu 16d-2 telephone

Feature button
Then "26"

SOURCE: HOW DO I GET THE ELECTRA ELITE IN MY OFFICE TO

you need to acces program mode and change 4-01 to assign ringing for the extensions you want to ring. ldtsnj.com

SOURCE: I have a NEC DTU-16D-2 phone system. The Speaker

Press Feature and then 1. This will turn on the MIC.